Feed mechanism for sewing machines



06f. 15, 1940. V H. LE VESCQNTE 2,218,287

FEED MECHANISM FOR SEWING MACHINES Filed Dec. 31; 1956 3 Sheets-Sheet 1 D/RFCT/O/V OFFEED/NE 1 M44 if F245" 5- II x1 F as WITNESSfi' I N VEN TOR.-

TTORNEYS.

' Harold JLaWsmniz,

O 1 1940- H. J. LE VESCONTE 2,218,287

FEED MECHANISM FOR SEWING MACHINES Filed Dec. 31, 1936 3 Sheets-Sheet 2 Win/555% H INVENTOR- 1 imrold. J LEWSLbH/ M ATTORNEYS;

Oct. 15 1 40.

H. 3. LE VESCONTE 2,213,237

FEED MECHANISM FOR SEWING MACHINES Filed Dec. 31, 1956 3 Sheets-Sheet 3 W I TNESSE INVENTOR: ifamld JLe Wswnia,

A TTORNE Y.

Patented Oct. 15, 1940 UNITED STATES FEED MECHANISM FOR SEWING MACHINES Harold J. Le Vesconte, Western Springs, 11]., as-

signor to Union Special Machine Company, Chicago, 111., a corporation of Illinois Application December 31, 1936, Serial No. 118,476

' 13 Claims.

This invention relates to feed mechanism for sewing machines, particularly for rotary hook lockstitch sewing machines; and it has more especial reference to feed mechanism of the type disclosed in a co-pending application Serial Number 51,992, filed on November 29, 1935, by Norman V. Christensen, Clarence C. Smith and George Sauer, wherein both the up and down or lift movements and the horizontal to and fro or feed movements of the feed dog are derived from a. single rotary actuator.

My invention has for its general aim to simplify feed mechanism of the type referred to with a view toward making possible the communication of feed and lift movements from the single rotary actuator through interpivoted intervening parts, so that friction and wear of the mechanism is reduced to a minimum.

Another object of my invention is to attain the above indicated advantages in a feed mechanism wherein the horizontal and vertical components of motion of the single rotary actuator are respectively converted into horizontal forward or reverse feed movements and into lift movements of the feed dog.

Another object of my invention is to secure such movements of the feed dog without the necessity for first decreasing the initial motion received from the rotary actuator and afterwards increasing it as heretofore.

Another object of my invention is to attain all the foregoing advantages in a feed mechanism having its parts so arranged as to provide adequate space for the fingers in the vicinity of the rotary hook in order that bobbin changes may be effected with the utmost ease and rapidity.

Other objects and attendant advantages will appear from the following detailed description of the attached drawings, wherein 'Fig. I is a fragmentary cross sectional view of a lockstitch sewing machine conveniently embodying the feed mechanism of my invention.

Fig. II is a fragmentaryview of. the sewing machine partly in front elevation and partly in longitudinal section, taken as indicated by the arrows IIII in Fig. I.

Fig. 111 is a view partly in plan and partly in plan section, taken as indicated by the arrows III-III in Figs. I and II.

Figs. IV, V and VI are detail perspective views of certain parts of the feed mechanism; and

Figs. VII and VIII are diagrammatic views of the feed mechanism.

The sewing machine herein delineated for convenience of illustration has a horizontal work support I with a standard 2 rising from one end thereof for an overhanging arm (not shown) which terminates in a head 3. Suitably guided for vertical reciprocation in the head 3, is a needle bar 4 with a needle 5 at its lower end adapted to cooperate with a rotary hook 6 (shown in dot and dash lines in Fig. I) below the work support I at the forward end of a short longitudinal shaft I, which, see Figs. II and III, extends through a replaceable bushing 8 into an oil housing 9 pendant from the work support I. Continuous rotary motion is imparted to the shaft 1, through a pair of intermeshing spur gears I0, I I, from a main longitudinal shaft l2 which extends through bushings l3 and i l in the opposite side walls of the housing 9 rearward of said shaft 1 in the direction of feeding. The shaft l2 may be driven by any suitable means, for example such as shown and described in co-pending patent application Serial Number 670,186, filed by Norman V. Christensen and Charles F. Rubel on May 9, 1933. The presser foot 15 of the sewing machine is secured to the lower end of a presser bar 16 located somewhat rearward of the needle bar 4 in the direction of feeding, and like said needle bar, confined to vertical movement in the head 3.

Coming now to the improved feed mechanism with which the present invention is more especially concerned, it will be observed that the same includes a carrier in the form of a horizontal bar I! which extends transversely of the machine above the level of the rotary hook shaft 1 and which is arched as at It near its forward end (as considered in respect to the front of the machine) in the vicinity of the rotary hook 6, as shown in Fig. I. Secured by apair of screws 19 to the arched portion it of the carrier bar I! is a feed dog 20 whereof the toothed portions extend upward, in the region of the presser foot 15, through a correspondingly configured slot 2! of the throat plate 22 of the machine, which latter, after customary practice, is recessed into the top of the work support. At its rear end, the carrier bar I! is formed with a boss 23 in which is secured, by a set screw 25, a pivot pin 26 whereof the opposite ends are engaged in spaced bearing bosses 21 (Fig. III) at the top of the vertical arm 28 of a bell crank rocker '29. As shown, this rocker 29 is secured to the medial portion of a shaft whereof the ends are journalled in replaceable bushings 3| fixed in pendant bearing lugs 32 of the work support I. At its front end, the feed bar ll has a pivotal connection 33 with the top of a vertical link 34 of which the lower end in turn is pivotally connectedat 35 to the end of the relatively short inwardly-extending horizontal arm 36 fast on one end of a shaft 31. As shown, the shaft 31 is journalled in another pendant bearing lug 38 of the work support I, and to its other end is secured, by means of a set screw 39, a relatively longer horizontal arm 40 which reaches inward from the front of the machine to a point immediately below the main shaft l2 where it is connected by a short upright strap link 4| with a rotary actuator in the form of a crank pin 42 in a disk at the end of said shaft. As shown in Figs. II and VI, the link 4| is clevised at its lower end as at 43 to receive the end of the arm 40 and apertured to engage a pivot pin 44 which latter is fixed in said arm by a set screw 45. Thus, through the rocker jointly consituted by the arms 36 and 40 and the connecting shaft .31, and the links 34, 4!, the vertical component of movement of the crank 42 is converted into reduced up and down movements of the feed dog carrier bar l1.

For the purpose of converting the horizontal component of rotation of the crank 42 into reduced horizontal to and fro movements of the feed dog, said crank is also coordinated, through a horizontal strap link 46 with the swinging end of an oscillating member or lazy bar 41 which is fulcrumed on a screw stud 48 at the lower end of a supporting arm 49. By means of a set screw 50, the supporting arm 49 is secured to another longitudinally extending shaft beneath the work support I, which shaft is journalled, with capacity for rotative adjustment in the thickened end wall 52 of the gear housing 9. The upper end, of the oscillating member 41 is reversely clevised as at 53 (see Figs. I and IV) to extend over the end of the link 46 and the corresponding end of a drop link 55 for pivotal connection to them by a transverse pin 56 which is fixed in said oscillating member by set screws 51. The drop link 55 is clevised at its lower end as at 58 (Figs. I and V) to embrace the end of the horizontal arm 59 of the bell crank rocker 29 whereto it is pivoted by a transverse screw stud 60, said arm 59, it will be noted, being of the same length as the arm 28. As a consequence of the described construction and arrangement of the component parts of the mechanism, ample room is provided in the vicinity of the rotary hook 6 so that bobbin changes can be easily and quickly effected.

With the supporting arm 49 for the oscillating .member 41 set in the full line position shown in diagrammatic Fig. VII and the shaft l2 rotating in the direction indicated by the arrow A, the operation of the feed mechanism is as follows:

As the rotary actuator or crank pin 42 moves through a half rotation to position 420, the horizontal link 46 will be pulled rightward to the dot and dash line position 460. and the oscillating member 41 moved correspondingly about its fulcrum 48 t the dot and dash line position 41a. In the following, the drop link 55 will move to the dot and dash line position 55a and cause the bell crank rocker 29 to be moved counter-clockwise to the dot and dash line position 28a, 59a with resultant impartation of a leftward (forward) feed movement to the feed dog as indicated by the arrow B. As the crank 42 passes through the remaining half of its rotation, the

parts willall be returned to the full line positions so that the feed dog is moved through arelatively long stroke for the formation of a correspondingly long stitch by the sewing machine.

. Setting of the suspension arm 49 for the oscilthe center 56 moves, approaches the horizontal,

the shorter the stroke imparted the feed dog. Due to the fact that the arms 28 and 59 of the bell crank 29 are of equal length, the amount of movement obtained by the oscillating member 41 from the crank 42 is communicated directly to the feed bar I1, i. e. without being first decreased and afterwards increased as is the case in the feed mechanism of the application Serial Number 51,992 hereinbefore referred to.

With the fulcrum 48 for the oscillating member 41 placed on neutral or dead center in the vertical plane through the shaft 5!, it is evident that no movement whatever will be imparted to oscillating member 41 and the link 55 will be moved to the dot and dash line 6" positions with attendant swinging of the bell crank 29 clockwise (instead of anti-clockwise as before) about its fulcrum 30 and shifting of the feed dog rightward as indicated by the arrow B by the distance 2B--26a. Shortening of the reverse stroke will result upon shifting the fulcrum 48 of the oscillating member 41 to an intermediate position, for example to the position 48f whereupon the parts will be limited to movement between the dotted line and the dash line I and g positions in the diagram. Thus, here again, it will .be apparent that the nearer the arc, through which the center 56 moves, approaches the horizontal, the shorter will be the stroke of the feed dog. Any suitable means, such as disclosed for example in U. S. Patent No. 2,035,508, granted to George Sauer and Clarence C. Smith on March 31, 1936, may be employed for the purpose of manually adjusting the supporting arm 49 for the oscillating member 41 to effect reversals in the operation of the feed mechanism and changes in the stitchlength, without affecting the timing i. e., constant relation of mid-stitch to the needle position.

From the foregoing disclosure, it will be seen that I have provided a simple and reliable feed mechanism in which the component parts are well-balanced and coordinated solely through pivotal joints which are substantially frictionless and which favor high speed operation of the sewing machine.

Having thus described my invention, I claim:

1. Feed mechanism for sewing machines comprising a feed dog and a carrier therefor; a rocker with horizontal and vertical arms to the latter of which arms one end of the carrier is pivotally connected; a drive shaft and a rotary actuator thereon; a horizontal link connected at one end arm of the rocker; an oscillating member coordinating the two links, whereby to and fro movements are imparted to the carrier; and means for also imparting up and down movements to the carrier.

2. Feed mechanism for sewing machines, com- .prising a feed dog and a carrier therefor; a rocker with horizontal and vertical arms of equal length to the latter of which arms one end of the carrier is pivotally connected; a drive shaft and a rotary actuator thereon; a horizontal link connected at one end to the rotary actuator and having its other end connected by a vertical link, with the horizontal arm of the rocker; an oscillating member coordinating the two links whereby to and fro movements are imparted to the carrier; and means'for also imparting up. and down movements to the carrier.

3. Feed mechanism for sewing machines comprising a feed dog and a carrier therefor; a rocker with horizontal and vertical arms to the latter of which arms one end of the carrier is pivotally connected; a drive shaft and a'rot-ary actuator thereon; a horizontal link connected at one end to the rotary actuator and having its other end connected by a vertical link with the horizontal arm of the rocker: an oscillating member coordinating the two links, whereby to and fro move-l nn a drive shaft and a rotary actuatorthereon; a horizontal link connected at one end to the rotary actuator and having its other end connected by a vertical link with the horizontal aim of the rocker; an oscillating member coordimatin the two links whereby to and fro movements are imparted to the carrier; means for also imparting up and down movements to the carrier; and means' whereby the fulcrum of the oscillating member can be shifted to reverse the action of the carrier.

5. Feed mechanism for sewing machines comprising a feed dog and a carrier therefor; means supporting the carrier at one end with capacity for substantially horizontal movement; a drive shaft and a rotary actuator thereon; a rocker having relatively long and short horizontal arms; a link connecting the long arm of said rocker with the rotary actuator; a link connecting the short arm of the rocker to the opposite end of the carrier for moving the. latter up and down; and means for also imparting horizontal feed movements to the carrier.

6. Feed mechanism for a lockstitch sewing machine with a rotary hook, comprising a feed dog and a carrier bar therefor, said carrier bar extending horizontally above the'level of the rotary hock shaft of the machine: a drive shaft inward of the rotary shaft in the direction of feed and 1 having a rotary actuator thereon; a rocker fulcrumed forward ofthe rotary hook shaft, said rocker having a relatively short inwardly-extending horizontal arm and a relatively long inwardly-extending horizontal arm under-reaching the rotary hook shaft; a vertical link forward-of the rotary hook shaft and connecting the front end of the carrier bar to the short arm of the rocker: a vertical link connecting the long arm of the rocker with the rotary actuator whereby up and down movements are imparted to the carrier; and means for also imparting to and fro movements to the carrier.

7. Feed mechanism'for 'a lockstitch sewing machine with a rotary hook, comprising a feed dog and a carrier bar therefor, said bar extending horizontally above the level of the rotary hook shaft of the machine; a drive shaft inward of the rotary shaft in the direction of feed and having a rotary actuator thereon: a rocker fulcrumed forward of the rotary hook shaft, said rocker having a relatively short inwardly-extending horizontal arm and'a relatively long inwardly extending horizontal arm under-reaching the rotary hook-shaft; a vertical link forward of the rotary hook shaft and connecting the front end of the carrier bar to the short arm of the rocker; a vertical link connecting the long arm of the 1 rocker with the rotary actuator whereby up and down movements are imparted to the carrier; a bell crank rocker with vertical and horizontal .arms rearward of the drive shaft, to which verticonnected by-a'vertical link with the horizontal arm of the bell crank rocker; and an oscillating member coordinating the last mentioned links whereby horizontal to and fro movements are imparted to the carrier.

8. Feed mechanism for a lockstitch sewing machine with a rotary hook, comprising a feed dog and a carrier bar therefor, said bar extending horizontally above the level of the rotary hook shaft of the machine: a drive shaft inward of the rotary hook shaft in the direction of feeding and having a rotary actuator thereon; a rocker fulcrumed forward of the rotary hook shaft. said rocker having a relatively short inwardly-extending horizontal arm and a relatively long inwardly-extending horizontal arm under-reaching the rotary hook shaft; a vertical link forward of the rotary hook shaft connecting the front end of the carrier bar to the short arm of the rocker; a vertical link connecting the long arm of the rockor with the rotary actuator; and means rearward of the drive shaft and coordinated with the rotary actuator for imparting to and fro movements to the carrier.

9. Feed mechanism for sewing machines comprising a feed bar with a feed dog mounted thereon between its ends; a shaft carrying a crank; a

pair of pitmans independently connected to the -dog without causing any change in the timing of such movement 10. Feed mechanism for sewing machines comprising a feed bar with a feed dog mounted thereon between its ends; a' shaft carrying a crank; a pair of pitmans independently connected to the crank; interposed means connecting one ofthe pitmans with one endof the feed bar whereby to and fro movements are imparted to the feed dog from the crank; interposed means connecting the other pitman with the other end of the feed bar whereby up and down movements are imparted to the feed dog from said crank; and means included in the first mentioned interposed means for reversing the to and fro movement of the feed dog without causing any change in the timing of such movement.

1'1. Feed mechanism for sewing machines comprising a feed bar with a feed dog mounted thereon between its ends; a shaft carrying a crank; a pair of pitmans independently connected to the crank; interposed means connecting one of the pitmans with one end of the feed bar whereby to and fro movements are imparted to the feed do from the crank; interposed means connecting the other pitman with the other end of the feed bar whereby up and down movements are imparted to the feed dog from said crank; and means embodied in the first mentioned interposed means for varying the to and fro movement of the feed dog and for reversing it without causing any change in the timing of such movement.

12 Feed mechanism for sewing machines comprising a shaft with a. crank thereon; a feed bar over-reaching the shaft and carrying a feed dog intermediate its ends; a pair of pitmans inde-.

pendently connected to the crank; interposed means connectingone of the pitmans with one end of the feed bar whereby to and fro movements are imparted to the feed dog from the crank; in-

terposed means connecting the other pitman with the other end of the feed bar whereby up and down movements are imparted to the feed dogpair of pitmans independently connected to the crank; a system of links and motion reducing arms interposed between one of the pitmans and one end of the feed bar, whereby to and fro movements are imparted to the feed dog from the crank; another system of links and motion-reducing levers interposed between the other pitman and theother end of the feed bar whereby up anddown movements are imparted to the feed dog from said crank; and'means included in the first mentioned interposed means for varying the to and fro movement of the feed dog without causing any change in the timing of such movement.

HAROLD J. LE VESCONTE 

